Ultrasonic testing of fitting assembly

ABSTRACT

Apparatus and method for determining relative and/or absolute axial position of a conduit end within a fluid coupling includes application of input ultrasonic energy in the form of transient shear waves and analyzing the reflected energy. Application of the input energy collected at different radial positions about a first axial location is used with wavelet based correlation techniques to better analyze the reflected energy signals. Quality of the abutment between the conduit end and a surface associated with the coupling may also be determined as a separate or combined feature of the axial position determination.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/876,150filed Oct. 22, 2007 for ULTRASONIC TESTING OF FITTING ASSEMBLY which isa continuation of U.S. Ser. No. 10/518,337 filed on Dec. 15, 2004, nowU.S. Pat. No. 7,284,433, issued on Oct. 23, 2007, for ULTRASONIC TESTINGOF FITTING ASSEMBLY FOR FLUID CONDUITS WITH A HAND-HELD APPARATUS, whichis a national phase entry under 35 U.S.C. §371 and claims priority toInternational Application No. PCT/US2003/19133, with an InternationalFiling Date of Jun. 17, 2003, for ULTRASONIC TESTING OF FITTINGASSEMBLY. which claims the benefit of U.S. Provisional patentapplication Ser. No. 60/389,394 filed on Jun. 17, 2002 for ULTRASONICFITTING ASSEMBLY VALIDATION, the entire disclosure of which is fullyincorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The invention relates generally to apparatus and methods fornon-destructive evaluation of fitting assemblies after assembly iscompleted. More particularly, the invention relates to using mechanicalenergy to make evaluations of the fitting assembly.

BACKGROUND OF THE INVENTION

Fluid handling equipment, whether the fluid is gas, liquid, combinationof gas and liquid, slurries and so on, may use many fluid controldevices that are connected together with the use of fittings. Typicalfluid control devices include valves, regulators, meters and so on thatare interconnected in a fluid circuit with either tube or pipe. Thefittings may take on a wide variety of designs, including but notlimited to single ferrule and multi-ferrule tube fittings, variousclamping arrangements using elastomeric seals, gripping rings and so on.For purposes of this disclosure we refer to tube and pipe as “conduit”because the present invention may be used with either tube or pipe.

Common to nearly all fluid circuits that use fittings to connect conduitto a flow control device or process is the desire to verify in anon-destructive manner that a fitting has been fully assembled. Mostconnections via fittings involve the positioning of a conduit within afitting body or other structure associated with a fluid coupling(referred to herein as a fitting assembly of a conduit and coupling)such that an end of the conduit abuts a shoulder or wall of the fittingbody or other structure. This abutment or “bottoming” as we also referto it herein, is usually desirable as it allows that gripping device,such as a ferrule, to be installed onto the conduit without the conduitmoving axially.

Inherent in the assembly process, however, is the practical circumstancethat once the fitting is installed there is no cost-effectivenon-destructive way, known to date, to determine that the conduit isfully bottomed. For example, it is known to use x-rays to observe thefitting condition, however, this is a very expensive process and simplynot practical for many if not most assemblers. Various techniques areknown that are used to verify proper installation of the fittingcomponents, or to verify proper pull-up based on the number of turns ofa fitting nut or axial displacement of the conduit relative to the nut.For example, the fitting may be disassembled after pull-up, visuallyinspected and then reassembled, but such steps are time consuming andcostly. In another known technique, the tubing may be pre-marked in anappropriate manner prior to assembly, but this technique is subject toerror in the marking or interpretation process. None of these techniquescan absolutely determine in a final assembled fitting that the conduitis bottomed, and also determine the nature or quality of the contact orabutment between the conduit and the associated structure.

The need exists therefore to provide process and apparatus fornon-destructive analysis and evaluation of whether a conduit is properlybottomed within a fitting.

SUMMARY OF THE INVENTION

The invention contemplates in one aspect determining position of aconduit end using input energy applied to the conduit. In one exemplaryembodiment, ultrasonic energy emitted from a shear wave transducer isapplied to the conduit and propagates through the conduit as mechanicalwaves. Alternatively or in combination, the input energy may be appliedthrough one or more of the fluid coupling components such as the fittingbody, for example. Reflected energy (also sometimes referred to hereinalternatively as return signals, return energy, return energy signals,reflected signals or reflected energy signals) is converted intoelectrical signals by the transducer and these electrical signals areanalyzed to determine position of the conduit end. In a specificexemplary application the invention may be used to determine theposition of an end of the conduit within a fluid coupling installedthereon. In alternative applications, the invention may be used todetermine proper assembly of one or more of the ferrules in a single ormulti-ferrule tube fitting by detecting a characteristic of the tubebite or indentation typically associated with ferrule-type tubefittings, such as, for example, the axial location thereof or thepresence/absence thereof.

In accordance with another aspect of the invention, correlationtechniques are used to more clearly discriminate the reflected energysignals. In one exemplary embodiment, ultrasonic energy is applied tothe conduit at different radial positions about a first location of theconduit that is axially spaced from the conduit end. Reflected energysignals are correlated to determine relative axial position of theconduit end. Noise reduction may also be applied to the return signals.

In accordance with another aspect of the invention, the quality and/ornature of contact between the conduit and a surface associated with afluid coupling installed on the conduit end may be determined. In oneexemplary embodiment, ultrasonic energy is applied to the conduit andthe amplitude of reflected energy is analyzed to determine the qualityof the contact or bottoming of the conduit end against the surfaceassociated with the fluid coupling, such as, for example, whether theconduit end is fully bottomed, partially bottomed or not bottomed.Correlation analysis may also be used in connection with this aspect ofthe invention.

In another embodiment of the invention, a tool is provided thatintegrates a source that applies mechanical energy waves, an analyzerthat determines the characteristics of a fitting assembly as a functionof reflected portions of energy waves, or both, with a gap gauge.

These and other aspects and advantages of the present invention will bereadily appreciated and understood from the following detaileddescription of the invention in view of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prior art two ferrule flareless tube fitting as an exemplaryfluid coupling that the present invention may be used with, illustratedin half-view longitudinal cross-section;

FIG. 2 is an elevation of a fluid coupling assembly and the presentinvention;

FIG. 3 is a functional block diagram of an analyzer in accordance withthe invention; and

FIG. 4 is an end view of an optional configuration for an ultrasonictransducer location in accordance with another aspect of the invention.

FIG. 5 is an alternative embodiment wherein a source and/or an analyzeris integrated with a hand-held tool, such as a gap gauge.

FIG. 6 is the tool shown in FIG. 5 implemented through the fitting neck.

FIG. 7 is the tool shown in FIG. 6 implemented through the tube and nut.

FIG. 8 is an assembly of fittings wherein the tool of FIG. 5 can beimplemented.

DETAILED DESCRIPTION OF THE INVENTION 1. Introduction

The present invention is directed to apparatus and methods relating todetermining position of a conduit within a fluid coupling installed onthe conduit. This determination may include, separately or combined,determining the axial position of an end of the conduit within a fluidcoupling, and determining the quality of contact between the conduit anda surface associated with the fluid coupling.

Determining the axial position of a conduit within a fluid coupling isparticularly useful, for example, with tube fittings of the type thathave a threadably coupled nut and body and at least one ferrule that isused to provide a fluid tight coupling between the tube end and thebody. Although the invention is described herein with particularreference to its use with a two ferrule flareless tube fitting, thoseskilled in the art will readily appreciate that the invention may beused in many other applications, and generally to any applicationwherein it is desired to determine the relative and/or absolute axialposition of an end of a conduit, such as tubing or pipe, whether theconduit end is positioned with a fluid coupling, a fluid flow device orso on.

Determining the nature or quality of contact is also particularlyuseful, for example, with the aforementioned tube fittings. Inparticular, the fitting body includes a generally radial shoulderagainst which the tube end is preferably abutted after a completepull-up of the fitting. By “pull-up” is simply meant the final assemblyand tightening of the coupling nut (beyond the initial finger tightassembly) and body so as to secure the one or more ferrules onto thetube end in a seal-tight manner. The quality of this abuttingrelationship is affected by many factors, including but not limited to,the facing operation of the tube end, such as the degree of flatness andsquare alignment of the tube end, the nature of the radial shoulder inthe body including its flatness and square alignment, the amount of tubedeformation that may occur during pull-up, the amount of compressiveload between the tube end and the body shoulder, and so on. The qualityof the bottoming is therefore a general reference to the completeness ofthe bottoming and the load between the abutting surfaces, as exhibitedby the nature of the contact in terms of the amount of contact area, thecharacteristics of the abutting surfaces and so on. The particularcharacteristics of quality and nature of the abutment may be selected asrequired for a particular application. Again, the invention will findapplication beyond two ferrule flareless tube fittings, and may be usedin many applications wherein it is desired to determine the quality ofthe abutment between a conduit end and a surface in a fluid element suchas a tube fitting, a flow control device and so on. In many couplingapplications, simply knowing the quality of the conduit end insertion,for example whether the conduit end is fully bottomed, partiallybottomed or not bottomed, is the most useful information, regardless ofthe ability to detect axial position of the conduit end.

In the exemplary embodiments herein, the invention is realized usingultrasonic energy as an input energy signal. The more specific, but notnecessarily required, characteristics of the ultrasonic energy in theexemplary embodiments is ultrasonic energy in the form of a generallycontinuous mechanical wave or waves having one or more discontinuities.In other words, the input energy may be applied as a series of one ormore transient waveforms. The input energy signal in the exemplaryembodiments therefore is in the form of one or more packets or pulses ofthe energy waveform. By “pulse” or “packet” we do not intend to restrictthe waveform of the input signal to any particular or required waveformshape or characteristic either in the time, frequency, wavelength oramplitude domains. In the exemplary embodiments, the input energy signalis realized in the form of a transient signal having one or moreharmonic waveforms with decreasing amplitudes over the time duration ofthe transient signal. The input waveform characteristics may be selectedto facilitate analysis of the return signals, such as by the correlationtechniques described herein. Alternatively, the applied waveform may beany Fourier series waveform for example, including an impulse harmonicwaveform, a square wave, and so on. Those skilled in the art willappreciate that the invention may be used with any convenientlyavailable form of reflectable mechanical energy, as distinguished fromelectromagnetic energy such as x-rays, that is transmitted by pressurewaves in a material medium, such as, for example, the conduit or one ormore parts of a fluid coupling, and detected therefrom.

While the invention is described and illustrated herein with particularreference to various specific forms and functions and steps of theapparatus and methods thereof, it is to be understood that suchillustrations and explanations are intended to be exemplary in natureand should not be construed in a limiting sense. For example, thepresent invention may be utilized with any fluid coupling between aconduit and a fluid flow member including but not limited to anotherconduit. The term fluid coupling therefore is used in its broadest senseto refer to any mechanical connection between a conduit end and anabutment surface of another fluid flow element. Furthermore, while theinvention is described herein with reference to stainless steel tubingand tube fittings, the invention will find application with many othermetals and indeed non-metal applications such as plastics, as well as totubing, pipe and so on.

Additionally, various aspects of the invention are described herein andare illustrated as embodied in various combinations in the exemplaryembodiments. These various aspects however may be realized inalternative embodiments either alone or in various other combinationsthereof. Some of these alternative embodiments may be described hereinbut such descriptions are not intended to be a complete or exhaustivelist of available alternative embodiments or modifications. Thoseskilled in the art may readily adopt one or more of the aspects of theinvention into additional embodiments within the scope of the presentinvention even if such embodiments are not expressly disclosed herein.Additionally, even though some features and aspects and combinationsthereof may be described herein as having a preferred form, function,arrangement or method, such description is not intended to suggest thatsuch preferred description is required or necessary unless so expresslystated. Those skilled in the art will readily appreciate that theinvention may be used with additional modifications, improvements andequivalents either known or later developed as substitute oralternatives for the embodiments described herein.

2. Detailed Description of Embodiments of the Invention

With reference to FIG. 1, there is illustrated a highly successful twoferrule tube fitting A. This fitting A is described in U.S. Pat. No.3,103,373 owned by the assignee of the present invention and fullyincorporated herein by reference. The illustration of FIG. 1 shows onlyone half of the fitting, it being recognized by those skilled in the artthat the other half of the view is identical about the centerline CL.

The fitting A includes a body B, a nut C that is threadably engaged withthe body B during finger-tight assembly and pull-up, a front ferrule Dand a back ferrule E. The fitting A is illustrated installed on aconduit, in this case in the form of a tube end T. The tubing T maycarry a media such as liquid, gas, slurry and so on. The assembly inFIG. 1 is illustrated in the pulled-up condition, with the ferrules Dand E plastically deformed so as to provide a fluid tight seal andstrong grip on the tube end T.

It is desirable that the inner end F of the tube end T abut at theregion TA defined at a radial shoulder G formed in the body B. Thisabutment is referred to as “bottoming” the tube end T and is desirableto provide a strong mechanical assemblage, including forming a good sealand having a strong tube grip, that can withstand environmentalconditions such as temperature variations and vibration effects. A sealmay but need not be formed at the abutment between the surfaces F and G.Whether a seal is formed there or not, it would be advantageous to beable to determine that the tube end is bottomed and the quality, natureor completeness of the contact. A tube end could be partially orincompletely bottomed by virtue of the assembler failing to properlyinsert the tube end sufficiently into the body B in accordance with themanufacturer's instructions.

A fully bottomed conduit end would be a condition in which there wassubstantial surface to surface contact between the conduit end and thebody shoulder and good solid mechanical contact or compressiontherebetween. A partially bottomed conduit end would be a condition inwhich, for example, there is not substantial surface to surface contactdue to poor end facing of the conduit end, a cocked or tilted conduit,or simply a lack of strong compression between the two abuttingsurfaces. A conduit end that is not bottomed would be a condition oflittle or no surface to surface contact or the presence of an actualaxial gap between the non-abutting surfaces. Therefore, as used herein,the nature or quality of the contact between the conduit end and theabutting surface refers generally but not exclusively to variousfeatures either alone or in various combinations including the amount ofsurface area where contact is made, the force or load between theconduit end and the abutting surface, presence of a gap therebetween,lack of square alignment of the abutting surfaces, and so on.

With reference to FIG. 2 we illustrate a first embodiment of theinvention. An input energy source or input device 12 is coupled to theconduit T so as to apply mechanical input energy into the conduit T,wherein a portion of the applied input energy is reflected back orreturned. The source device 12 may be, for example, a transducer thatconverts an electrical drive signal into vibration or mechanical energy.One example is an ultrasonic transducer that emits a high frequencysignal which may be reflected or otherwise returned to the source 12 bya variety of conditions including but not limited to inclusions,micro-structural deformations, voids, the tube end F, and tubingdeformations or indentations such as the ferrule bite or compression.The source 12 is used as a transmitter as well as a receiver or sensorand converts the reflected energy that reaches the source 12 into acorresponding electrical signal. Alternatively, the transmitter andreceiver may be separate or different devices. The source 12 is coupledvia a cable 14 or other suitable connection to an electronicsarrangement 16. The electronics 16 includes appropriate circuitry thatgenerates the drive signal for the source device 12 and that receivesthe electrical signals from the source device 12.

We have found that—although a surface wave transducer or a delay linetransducer may be used to determine the bottomed condition of a tubeend, as well as proper assembly of the tube fitting, and that either ofthese transducers is a useful alternative to the exemplary embodimentherein—a preferred technique and device is to use a shear wavetransducer to apply the input energy to the conduit T. A shear wavetransducer is distinguished from a delay line transducer in that theshear wave transducer applies energy into an object generallylongitudinally or along the direction of the surface of the object,whereas a delay line transducer applies energy generally normal to thesurface, and thus may be used to determine wall thickness. The shearwave transducer is thus able to produce a better return reflection orecho of the end of the conduit, particularly when the conduit is onlypartially bottomed or completely not bottomed.

A suitable and exemplary transducer is a Phoenix-ISL shear wavetransducer model SSW-4-70 that is resonant at 4 Megahertz. Othertransducers commercially available or later developed will also besuitable for the present invention, and the invention is not limited tothe use of ultrasonic energy waves. Non-ultrasonic wave frequencies maybe used provided that adequate and detectable energy is reflected backfrom the tube end. It is also possible to use a tuned frequency thatprovides the strongest echo from the conduit end depending on theconduit dimensions, material, temperature, the fluid coupling associatedtherewith, and so on.

It is worth noting at this time that a particular advantage of thepresent invention is that it may be used to determine the bottomingcondition of a conduit within a fluid coupling in a non-destructivemanner, even while the fluid is present in the conduit. Thus there is noneed to necessarily purge the system or disassemble any components,although such may be desirable in some circumstances.

We have further found that easily interpreted data can be obtained afternoise filtering and performing correlation analysis to the reflectedenergy. We have moreover found that a Morlet wavelet function, wellknown to those skilled in the art as to its mathematical form, aids thefiltering function with the invention, however, the present invention isnot limited to using such a Morlet wavelet function. For example, othertypes of exponential sinusoidal wavelet functions, or other filteringfunctions, may be alternatively useful in some applications.

With reference to FIG. 3, we illustrate a detailed functional blockdiagram of the electronics arrangement 16 in the form of an analyzer. Itis desirable that the invention be realized in the digital analysisdomain, however, such is not required and it may be suitable in someapplications to perform analog or hybrid analog/digital analysis.

FIG. 3 also illustrates additional aspects of the invention relating tothe mounting of the source 12. In this example, the source 12 is a shearwave transducer and is firmly supported on a base 20 that can besuitably attached to or placed in contact with the conduit surface TS.The base 20 preferably is made of a high transmission material, such asacrylic resin, so that the energy emitted from the transducer face 22 iscoupled with good efficiency into the conduit T. The use of a base 20 orother suitable structure enhances the coupling because the base 20 canbe provided with a surface 24 that conforms to the surface profile ofthe conduit surface TS. This usually will be an improvement over simplytrying to position the typically flat transducer face 22 against acylindrical surface TS, however, in some applications, especially largediameter conduits, such a direct mounting may be useable. A suitable lowattenuation coupling material may also be applied between the basesurface 24 and the conduit surface TS. A suitable low attenuation liquidcouplant may be water for example, however other coupling material suchas solid or paste may be used, such as for example, latex or siliconerubber or AQUALENE™ available from R/D Tech. The use of a couplingmaterial may be omitted in cases where the signal coupling between theconduit and the transducer does not adversely attenuate either the drivesignal into the conduit or the reflected energy back into thetransducer.

FIG. 3 illustrates that the base 20 may be configured so that thetransducer face 22 is angled away from normal towards the conduitlongitudinal axis CL. In this manner, the input energy enters theconduit structure at an angle θ_(R). We have found that a suitable rangefor θ_(R) is from about greater than 0° to about 90°, more preferablyabout 45° to about 85°, and most preferably about 65° to about 75°.However, the selected angle for θ_(R) in any particular application maybe selected based on the angle that produces the best or most usefulreturn energy profiles. Materials having appropriate indices ofrefraction may be selected to allow refraction to assist in the inputenergy entering the coupling assembly at the desired angle θ_(R).

With continued reference to FIG. 3, the analyzer 16 may be realized inthe form of any suitable digital processor including but not limited toDSP, microprocessors, discrete digital circuits and so on. The analyzerprocessor 16 may conveniently be any commercially available or laterdeveloped circuit that is programmable in accordance with programmingtechniques well known to those skilled in the art, to carryout thefunctions described herein. The analyzer processor 16 thus includes asignal generator 26 that produces a suitable drive signal that iscoupled to the transducer 12 via a suitable cable or wire 28. Theanalyzer processor 16 further includes a filter function 30 that may beused for noise reduction, since the electrical signal from thetransducer 12 will typically include a substantial amount of backgroundundesired noise. Any suitable filter design in circuitry or softwarewell known to those skilled in the art may be used. Note that in FIG. 3the noise filtering function is performed on the analog signal from thetransducer 12. Alternatively, digital filtering may be performed incases when the transducer signal has been digitized. Still farther, afilter function may be included in the transducer itself, and specialshielding on the cables and transducer assembly may be used as requiredto further reduce noise.

The filter function 30 receives the electrical output signal from thetransducer 12 via a cable or other suitable connection 32 (note that thewire 32 and the wire 28 are part of the aforementioned cable 14 of FIG.2).

The filtered signal from the transducer 12 is then input to aconventional analog to digital (A/D) converter 34. The A/D converter 34converts the electrical signal from the transducer 12 into a digitizedsignal that can be conveniently stored in a storage device such as amemory 36. The memory 36 may be volatile or non-volatile memory or bothdepending on the type of data analysis to be performed.

In some applications, the reflected energy signal may have a verypronounced and easily discernible signal level that corresponds to theaxial position of the conduit end relative to the energy source 12. Notethat the axial position of the conduit end relative to the transducermay be determined either as an absolute number or a relative number, andis computed based on knowing the propagation speed of the energy throughthe conduit, as is well known in the art of ultrasonic analysis. If thereflected energy provides an easily discernible signal stored in thememory 36, then the controller 16 can simply be programmed to determinethe characteristics of the signal to ascertain the axial position of theconduit end.

In accordance with another aspect of the invention, the relativestrength of the reflected energy is an indication of the quality of thebottoming. We have found that when there is good or complete bottoming,very little energy is returned from the conduit end because the energypasses through into the fitting body material (and/or other contactingstructures) and there is thus a substantial attenuation in the reflectedor returned energy. Thus interestingly, the absence of a strongreflected energy level actually indicates excellent bottoming. For anun-bottomed conduit end, a high and sharply pronounced reflected energylevel is returned due to reflection at the gap interface between theconduit end and the body shoulder. For a partially bottomed conduit end,the reflected energy will be somewhere in between a fully bottomedconduit end and an un-bottomed conduit end. Test samples and empiricaldata may be used to calibrate the system 16 as required.

We have further found through experimentation, however, that themechanical complexity of a typical fluid coupling and conduitmicro-structure renders a nice clean easy-to-detect reflected energysignal to not be a practical reality. Instead, all sorts of false ornon-repeatable echoes may arise. Furthermore, we have found that for asingle axial location of the transducer relative to the conduit end, thecircumferential position of the transducer may significantly influencethe nature of the reflected energy. For example, the reflected energyfrom the conduit end may not always appear at the same time delay markerwhen the transducer is moved about different circumferential positions,even at the same axial location, on the conduit. We attribute this tomicro-variations in the conduit and the fluid coupling structure, butwhatever the causes may be, the practical consequence is that theytypically will be present.

In accordance then with another aspect of the invention, the energyapplied into the conduit T is done at two or more circumferentialpositions about the selected axial location of the source transducer 12.This is illustrated in FIG. 4 wherein reflected energy data is collectedand stored for two or more circumferential positions of the sourcetransducer 12 about the conduit at the axial location selected. This canbe performed using a plurality of transducers positioned at differentpositions about the conduit T, or more simply by repositioning a singletransducer 12 and then collecting data at each location as indicated bythe dashed lines in FIG. 4. The different positions may be but need notbe evenly spaced about the conduit.

Each application of input energy at a particular circumferentialposition produces reflected or return energy that is converted into anelectrical signal, filtered and stored as previously described herein.Data is collected for two or more, and preferably about three, differentcircumferential positions at the selected axial location of thetransducer (which in the exemplary embodiment is just behind the nut Cof the fitting assembly A.) A correlation function 40 is then applied tothe set of data from the plurality of circumferential positions. Thecorrelation analysis substantially eliminates or “filters” the randomreturn energy signals from the micro-variations in the conduit becausetheir positions relative to the applied energy transducer source 12changes as the transducer is repositioned about the conduit T. Theconduit end relative position, however, does not, and correlationanalysis distinctly discriminates the corresponding signal. Thecorrelation analysis may be conventional, such as for example but notlimited to, the analysis disclosed in Correlation Analysis of SpatialTime Series Datasets: A Filter and Refine Approach, Zhang, Huang,Sheldiar and Kumar, University of Minnesota, Technical Report Abstracts,2001, the entire disclosure of which is fully incorporated herein byreference. We have found that the selected signal correlation analysismay be significantly facilitated by optionally but preferably using thewavelet based correlation method disclosed in Complex Wavelet Analysisof Ultrasonic Signals, Hull, Yang, and Seymour, to be published inIMechE (Institution of Mechanical Engineers, London), June, 2003, theentire disclosure of which is fully incorporated herein by reference,and which may be implemented/programmed in software or firmware usingconventional and well known techniques. The analyzer 16 can thus producean output 42, in any suitable form including but not limited to a visualoutput, printed output and so on, of the quality of the conduit endbottoming and, if so desired or alternatively separately desired, theabsolute or relative axial position of the conduit end as a function ofthe axial location of the source 12.

The present invention contemplates not only the structure of theaforementioned apparatus, but also the methods embodied in its use, andfurthermore a method for determining position of a conduit end within afluid coupling and a method for determining the quality of the bottomingof a conduit end against a structural surface. Such a method includesthe steps of applying energy into the conduit structure, detectingreflected or returned energy from the conduit end and determining theposition of the conduit end as a function of the location of the source.In another method, the quality of the bottoming of a conduit end isdetermined by applying energy into the conduit structure, detectingreflected or returned energy from the conduit end and determining thequality of bottoming of the conduit end as a function of the reflectedenergy signal strength. Both methods may be used alone or in combinationwith each other or other analysis, and both methods may optionallyutilize the above-described noise filtering and correlation techniques.

As some of the many available alternatives, the electronics 16 may beincorporated into any suitable package for use in the desiredapplication and environment. For example, the electronics 16 includingthe source 12 may be incorporated into a device or tool that also isused as a conventional gap gauge. The electronics 16 may produce anoutput of any desired format, and for example, could simply be a lightthat indicates a go/no go result of the bottoming of the tube end. Theelectronics may also incorporate intelligent rules based software suchas neural nets for calibration and/or analysis and may include the abovedescribed noise filtering and correlation techniques.

The source 12 may alternatively be configured to apply the input energyinto a component of the fluid coupling, rather than or in addition tothe conduit. This would only require a simply reconfiguration of theinterface geometry of the base 20 for example. Depending on the surfacefor mounting, the base 20 may even be unnecessary. For example, thesource 12 may apply the input energy into the fitting body B, such as atthe head or neck of the fitting body.

Still further, the present invention may be used to determine,separately or in combination with the conduit end position, otherevaluations of the fitting assembly. As described herein above, thepresent invention may be used to determine the position and abutmentcharacteristics of the conduit end. The invention may also be used todetermine the position and characteristics of other normal deformationsand structural variations of the conduit such as are associated with thefluid coupling, as such conditions may also produce reflected energy.For example, but not limited thereto, the invention may be used todetect the presence and/or location of the bite or tube indentation orcompression caused by one or more of the ferrules. By determining thatthe selected condition is positioned properly and has the desiredquality, the user may know that the fitting assembly has been properlycompleted, such as knowing that the ferrules are correctly installed andpulled up. Absence of such signals may indicate improper assembly orpull-up.

In another embodiment, the invention is a tool that can be used to checkboth the correctness of the geometric pull-up and the internal integrityof a twin-ferrule tube fitting. Using ultrasonic sensor(s) and amicroprocessor embedded with advanced mathematical software, the toolwill be able to detect if the tubing is fully bottomed against the tubebore shoulder (i.e. correct tube installation, See Feature 4). The mainadvantage of this design is to provide an alternative that isnon-destructive (e.g. actual disassembly/re-assembly of fitting) and lowin cost (relative to X-raying fitting connections) and greatly reducesthe potential for the product to be installed improperly.

The hand-held tool shown in FIGS. 5-7 verifies correct geometricpull-up, as shown in Feature 8 (i.e. 1¼ turns past finger-tight bygauging the “nut-to-body” gap) and detects if the tubing is fullybottomed against the tube bore shoulder. Further, use of the tool doesnot require the fitting to be disassembled and thereby eliminates theneed to use of X-ray equipment. The tube-gripping portion of the toolverifies the correctness of the geometric pull-up by gauging the“nut-to-body” gap. The nut-to-body gap is held consistent due to tightlytoleranced critical dimensions placed on the nut, ferrules, and fittingbody. This feature is designed such that the tool cannot fit in betweenthe nut and the fitting body when the required “nut-to-body” gap isreached. As such, the tool acts as a conventional gap gauge, asdisclosed in U.S. Pat. No. 3,287,813, the disclosure of which is fullyincorporated herein by reference. The back end of the tool detects ifthe tubing is fully bottomed against the tube bore shoulder, locatedinside the fitting body (i.e. correct tube installation). Using one ormore ultrasonic sensors and a microprocessor embedded with advancedmathematical software, the tool can selectively scan critical internalfeatures of the fitting body and components and notify the user, audiblyor visually, if the tubing is correctly installed. The tool may scan thefitting using any of the methods described herein above.

The invention has been described with reference to the preferredembodiment. Modifications and alterations will occur to others upon areading and understanding of this specification. It is intended toinclude all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof.

1. A method for evaluating a pulled-up condition of a fitting of thetype having a conduit assembled at one end to a fitting comprising abody, a nut, and a conduit gripping device, the method comprising thesteps of: pulling up the fitting on the conduit to form a fittingassembly wherein the conduit gripping device forms an impression on theconduit; applying mechanical energy into the fitting assembly at areference position; detecting at said reference position returnmechanical energy; and determining whether the conduit gripping deviceis correctly installed based on axial position of said impressionrelative to said reference position.
 2. The method of claim 1 comprisingtwo conduit gripping devices.
 3. The method of claim 2 wherein saidconduit gripping devices comprise a front ferrule and back ferrule. 4.The method of claim 1 wherein the conduit, nut, body and conduitgripping device are formed from stainless steel.
 5. The method of claim1 wherein said impression comprises a deformation formed by the conduitgripping device biting into the conduit.
 6. The method of claim 1wherein said impression comprises a deformation of the conduit from acompression of the conduit gripping device against the conduit afterpull-up.
 7. Apparatus for evaluating a fitting for conduits, theapparatus comprising: a fitting comprising a first component, a secondcomponent and at least one conduit gripping device; a conduit assembledwith the fitting to form a pulled-up fitting assembly, wherein theconduit gripping device forms an impression on the conduit after thefitting has been pulled-up; first means to apply mechanical energy intothe fitting assembly and to detect returned energy and produce a signalrelated thereto; and second means to determine axial position of theimpression on the conduit based on said signal.
 8. The apparatus ofclaim 7 wherein said first means comprises a transducer.
 9. Theapparatus of claim 8 wherein said transducer operates as both a sourceof the mechanical energy and a receiver of the mechanical energy. 10.The apparatus of claim 7 wherein said first means comprises anultrasonic transducer.
 11. The apparatus of claim 7 wherein said conduitgripping device comprises a ferrule.
 12. The apparatus of claim 7wherein the first component comprises a nut and the second componentcomprises a body, said nut and body being threadably joined together inthe pulled up fitting assembly.
 13. The apparatus of claim 12 whereinthe conduit, body, nut and conduit gripping device comprise stainlesssteel.
 14. Apparatus for evaluating a fitting for conduits, theapparatus comprising: a fitting comprising a first component, a secondcomponent and at least one conduit gripping device; a conduit assembledwith the fitting to form a fitting assembly, wherein the conduitgripping device forms an impression on the conduit after the fitting hasbeen pulled-up; first means to apply mechanical energy into the fittingassembly and to detect return mechanical energy and produce a signalrelated thereto; and second means to determine whether the conduitgripping device is correctly installed based on said signal.
 15. Theapparatus of claim 14 wherein said mechanical energy comprisesultrasonic energy.
 16. Apparatus for evaluating a fitting for conduits,the apparatus comprising: a fitting comprising a first component, asecond component and at least one conduit gripping device; a conduitassembled to the fitting to form a fitting assembly, wherein the conduitgripping device forms an impression on the conduit after the fitting hasbeen pulled-up; a source adapted to apply mechanical energy into thefitting assembly; a receiver adapted to detect return mechanical energyand produce a signal related thereto; and an analyzer that determineswhether the conduit gripping device is correctly installed based on saidsignal.
 17. A method for evaluating a pulled-up condition of a fittingof the type having a conduit assembled at one end to a fittingcomprising a body, a nut, and a conduit gripping device, the methodcomprising the steps of: pulling up the fitting on the conduit to form afitting assembly wherein the conduit gripping device forms an impressionon the conduit; applying mechanical energy into the fitting assembly;detecting return mechanical energy and producing a signal relatedthereto; and determining whether the conduit gripping device iscorrectly installed based on said signal.
 18. The method of claim 17wherein said mechanical energy comprises ultrasonic energy waves.
 19. Amethod for evaluating a pulled-up condition of a fitting of the typehaving a conduit assembled at one end to a fitting comprising a body, anut, and a conduit gripping device, the method comprising the steps of:pulling up the fitting on the conduit to form a fitting assembly whereinthe conduit should have a deformation at an expected axial position onthe conduit caused by compression of the gripping device when correctlyinstalled; applying mechanical energy into the fitting assembly;detecting return mechanical energy; and determining whether the conduitgripping device is correctly installed based on the presence or absenceof the deformation of the conduit at the expected axial position. 20.The method of claim 19 wherein said deformation comprises one or both ofa bite and radial compression of the conduit gripping device against theconduit.